1. Field of the Invention
The present invention relates to a device and a method for working a weld on a support sleeve for a printing or transfer form cylinder made of a metallic material.
2. Description of the Related Art
It is known from flexographic printing9 to apply sleeve-shaped printing and transfer forms to nickel sleeves produced by electroplating. These printing and transfer forms are pushed over a cylinder in a known manner using compressed air and are fixed to the cylinder by shutting off the compressed air supply.
A prior art sleeve-shaped offset printing form disclosed in German reference DE 41 40 768 A1 is produced from a metal plate that is cut to size in a rectangular shape. The rectangular shaped plate is then formed into a sleeve and the ends of the plate which face each other are connected by a weld. The entire outer surface are of this support sleeve is coated and exposed except for the weld. Another German reference DE 42 17 793 C1 discloses a prior art sleeve-shaped offset rubber blanket which is also produced from a cut-to-size support plate. A rubber coating is applied to the support plate in the flat state of the support plate and the support plate with the rubber blanket is then formed into a sleeve shape with the ends of the support plate being welded to one another along with the rubber coating for completing the sleeve. Although this prior art printing and transfer form performs printing without a cylinder groove, continuous printing can not be performed. That is, only printed products can be produced.
Prior art support sleeves suitable for continuous printing are disclosed by German reference 44 32 814 A1. The initial shape for these printing or transfer forms is a rectangular thin-walled plate piece that is formed into the desired hollow cylindrical shape by bending. The resulting edges pointing toward one another are firmly connected. The sleeve surface must then be worked to form a homogeneous circumferential outer surface for continuous printing. The working of the sleeve surface for creating a smooth surface is accomplished using known machining methods such as turning or grinding.
The object of the present invention is to provide a novel method and device for working the outer cylindrical surface of a support sleeve for a printing or transfer form made from a metal plate having the two ends firmly connected, such that the resulting support sleeve is suitable for continuous printing.
The object is achieved by a method for working the outer surface of a weld on a support sleeve for printing or transfer forms, comprising the steps of arranging a support sleeve having a substantially longitudinal weld on an abutment adapted for supporting an inner circumferential surface of the support sleeve at least in an area of the weld on the support sleeve, and compacting and smoothing the weld on the support sleeve by rolling a roller over the weld from outside the support sleeve along a longitudinal direction of the support sleeve.
The object is also achieved by an arrangement for working a substantially longitudinal weld on a support sleeve for a printing or transfer form, comprising an abutment having a longitudinal direction for receiving the support sleeve having the substantially longitudinal weld in a received position, a device movably arranged for moving along the longitudinal direction of said abutment, and a roller rotatably mounted on said device and facing said abutment, said roller moving with said device along the longitudinal direction such that said roller is rollable on the substantially longitudinal weld of the support sleeve receivable on said abutment for compacting and smoothing the weld.
The invention provide a method for smoothing the weld on a circumferential surface of a printing or transfer form so that no unevenness remains. The advantage of the invention is that the resulting sleeve may be coated or exposed in the region of the weld. If the sleeve is a transfer form, a rubber coating may be applied in the region of the weld. If the sleeve is a printing form, the printing form may be provided with an image using a material corresponding to a printing subject in the region of the weld.
Other objects and features of the present invention will become apparent from the following detailed description considered in conjunction with the accompanying drawings. It is to be understood, however, that the drawings are intended solely for purposes of illustration and not as a definition of the limits of the invention, for which reference should be made to the appended claims.
The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of the disclosure. For a better understanding of the invention, its operating advantages, and specific objects attained by its use, reference should be had to the drawing and descriptive matter in which there are illustrated and described preferred embodiments of the invention.